Telephone-exchange system



April 14, 1925. 1,533,153

7 S. B. WILLIAMS, JR

TELEPHQNE EXCHANGE SYSTEM 2 Shoots-Sheet 1 O O J 7 O O J w M: ME A 6amue/ 5. Williams J/:

I S. B. WILLIAMS. JR

TELEPHONE EXCHANGE SYSTEM Filed Aug. 1'7, 1920 Z'Sha'tk-Sheot 2 WNN lnvnfor. Samuel Williams Jr."

detented Apr. 1%, 15325.

UNITED STATES PATENT orrica.

SAMUEL B. \VILLIAMS, J'R., 0F BROOKLYN, ITEl/V YORK, ASSIGNOR 'IO WESTERN ELEC- TRIO COMPANY, INCORPORATED, 035 NEW YORK, N. EL, A CORPORATION OF NEW YORK.

'IELEPHONE-EXCI-IANGE ESYSTEIVI.

Application filed August 17, r920. Serial No. 4:04,!)79.

To a?! whom 516mm, concern Be it known that I, SAIJUEL B. d m LIAMS, 512, a citizen of the United States, residing .at- Brooklyn, in the county of Kings and State of New York, have iniented certain new and useful Improvements in lelephone-Erichange Systems, of which the'tollowing is a fulh-clea'r, concise, and exact description.

This invention relates to telephone systems and particularly to party line working in machine switching systems.

The object of the invention is to provide an improved device of the character set forth in the patent to Hovland, No. 1,158,221 of October 26, 1915. In accord ance with this object, an all relay circuit arrangement for accomplishing the desired results has been devised having certain novel features which will clearly appear as the description proceeds.

i In the drawings, Fig. 1 diagramniatically represents two party lines with means whereby they may setup connectionsi-or revertive calls. On the right of Fig. 1, 1s shown a circuit for two-party revel-tire calling and inFig. 2 is shown a circuit for tour-party revertive calling.

The arrangement of a rerertii'e call on a two-party line will first be described. Such a two-party line is shown in the lower lefthand corner of Fig. 1, with the stations 105 and 106 bridged across the line wires T and 1%, representing the tip and'ri ng sides of the line as they are spoken of by telephone men. The stations 105 and 106, as they are connected to the :line wires, are reversed with respect to each other so that ringing current traveling oyer the tip sidotoi the line will lind an open circuit at statimi .106, but will travel through the condenser and bell of station 105to ground. On the other hand, ringing current traveling over the ring side ct the liue will fini'l'ancpcn circuit .at sta tion 105 but will'fiow throughthe condenser and bell of station 106.

Let it be assumed that the subs iber at station 105 desires] to call the subscriber at station 106. He Will, therefore, upon removing his receiver from its switch hook cause the line switch, diagrammatically represented byjthe brushes 114, to connect to the selector switch 125. In order to make a. revertive call, the subscriber at station 105 must dial a special number. We will, in this case, assume that the special number is Upon manipulating his dial switch to send a train of five impulses, the brushes ot' selector switch 125 will be set on their fifth contacts, 107 to 100 inclusive. A circuit is thereupon established from ground, battery, left-hand wimling of relay 117 back contact and outer left-hand armature of relay 117, terminal 108, conductor .lt. through the substation at 105, conductor T; terminal 107, inner left-hand armature and back contact of relay 117, and the right hand winding of relay 115 to ground. Relay 115 is energized and establishes a circuit from ground, the armature and front contact of relay 115, the winding of relay 116 to battery and ground. Relay 116 attracts its armatures and at its left-hand armature, places a holding ground. on the terminal 109 of the calling line.

lVhen the subscriber at station 10.) has set up this connection, he replaces his receiver on its hook, whereupon the relay 1].?) becomes deenergized. Relay 116, however. is slow to release and therefore a circuit established from ground, the armature and back contact of relay 115, right-ha1ul armature and front contact of relay 116. armature and back contact of relay 124, the normal contacts of the right-hand armature of relay 123, and the winding of relay 117 to battery and ground. Relay 117 attracts its armatures and establishes a holding ground for relay 116 extending from ground, the inner right-hand armai ure and front contact of relay 117, and the winding of relay 116 to battery and ground. .\t. the saxno time, relay I17 establishes a ircuit [o the eucrgization of relay il l so that the interrupter 121 is comm-ted tolhc right hand armature'oi relay 110.

Special attention should be attached to the connection of relays 119 and 120. Upon the first closure of the circuit through interruptcr 121. ground is placed on the righthand armature of relay 110 through its bacl: contact, the winding of relay 120 and the righthand winding of relay 119 to battery and ground. delay 120 is energized in this circuit, but the right-hand winding of relay 119 being marginal, relay 119 does not become energized at this time. Relay 120 in attracting its armature extends ground from the left-hand armature of relay 118, the front contact and armature of relay 120, and the left-hand winding of relay 119, but this winding is short circuited at this time due to the ground at the back contact and righthand armature of relay 119 furnished through the interrupter 121. lVhen the interrupter 121 opens the circuit, relay 119becomes energized througha circuit including its left-hand winding, the winding of relay 120, and the right-hand winding of relay119 in series. 'lVhen the interrupter 121 again closes the circuit to ground, the winding of relay 120 will be short circuited due to the ground furnished at the right-hand armature and front contact of relay 119, and the ground furnished through the armature of relay 120. Thus, relay 120 becomes deenergized and relay 119 is held energized through its right-hand winding. As the mterrupter 121 again opens the circuit, relay 119 becomes deenergized. Thus, for two complete cycles of operation of the interrupter 121 there is a single complete cycle of operation of relays 119 and 120. v

Upon the energization of relay 117, a circuit is closed from a source of ringing current 126 through the back contact and outer left-hand armature of relay 122, the winding of relay 124,, the front contact and outer left-hand armature of relay 117, the ring side of the line, the condenser and bell of station 106 to ground, whereby the bell at station 106 is caused to ring. The bell at station 105, at this time, is short circuited due to the ground at the back contact and inner left-hand armature of'relay 122 being connected through the front contact and inner 7 left-hand armature of relay 117 to the tip side of the line. Upon the first energization of relay 119,. ground is extended from the left-hand armature and front contact of relay 118, the left-hand armature and front contact of relay 119 to the winding of relay 122. The armature of relay 122 now re verses the ringing current, connecting the source of ringing current to the tip side of the line and ground'to the ring side, whereby the bell at station 106 ceaSes to ring and the bell at station 105 begins to ring; As the interrupter 121functions, relays 119 and 120' will continue to operate, whereby relay 122 is intermittently energized and deenergizcd and the bells at stations 105 and 106 are alternately rung. When the party at station 106 removes his receiver from its switch hook, the current flowing through relay 124 is increased sulficiently to cause this relay to become energized. Thereupon the circuit for relay 117 is opened and relay 123 becomes energized in series withrelay 117 through the right-hand winding of relay 12.3. After relay 123 has attracted its armatures and opened the circuit of. relay 117, it remains energized through its left-hand winding. As relay 117 becomes deenergized, ringing cur rent is out off from both bells on the party line, and the subscriber at station 105 noticing that this bell no longer rings, removes his receiver from its hook in order tocominunicate with the subscriberat station 106.

'Talking current is furnished through the windings 01-, relay 115 wh1ch now becomes energized and furnishes ground to hold re-' lay 116 in place of the ground furnished by relay 117. I 7

It should be noted that if both subscribers replace their'receivers, this circuit will not again be set in operation to ring'the two bells since relay 123 has locked upto the ground on terminal 109. When both subscribers do replace their receivers, relay 115 becomes 'deenergized and after an interval, relay 116 retracts its armatures and removes the ground from terminal 109 whereupon the selector switch 125 and the line switch 114 are returned totheir normal position in any well-known manner.

In the upper left-hand portion of Fig. 1, there is shown a four-party line; the substation arrangement here is somewhat differ ent from that on a two-party line since a relay is required. Two of the stations, 101

and 104, are reversed with respect to the other two stations, 102 and 103. Stations 101 and 104 differ, in that in one the bell isbiased to respond to plus pulsating current only, and in the other, that is station 104, the bell is biased to respond to minus pulsating current only. The same difference applies to stations 102 and 103.

Let it be assumed that the subscriber at station 101 desires to call the subscriber at station 103. In the manner hereinbefore described, the subscriber atstation 101 will be required to dial the special number which we will assume tobe, in the present instance, 46. As he transmits the first series of four impulses, the selector switch 125 will be set on the terminals 110 to 112 inclusive, whereupon a relay, 215, will be energized in the same manner asrclay 115.was energized. Relay 215 in attracting lts'armature causes the energization of relay 1216 which places a ground on conductor 209 connected to terminal 112, to mark this particular circuit as busy and to hold'the selector switch 125 and the line switch 113 from releasing. he

subscriber at station 101 now dials the sectill 210 becomes essons lay 207, and the winding of relay 208 to battery .and ground. Relay 208 closes ,a cirofurelay 208, the left-hand armature and back contact of relay 219, the Winding of relay 220, and the left-hand winding of .relay 219to battery and ground. Relays 219 and 220 act in exactly .=the same manner as Clo-relays 119 and 1-20. Therefore, upon the first closureloit the right-hand armature and contact of relay 208, relay 220 energizes. hen this varmature is retracted, relay 219 becomes lenergized. llvhentthis armature is again attracted, relay 220 becomes .deenen gized, and When this armature is retracted tor "the second time, "relay 219 becomes deenergized.

Rela-y 20-1 upon energizing prepares a circuit for relay 202 lrom battery and ground. the winding of relay 202, the inner right-hand armature and front contact of relay 201, the back contact of "the lefthand armature of relay 220, but since-relay is energized at this ti1ne, t he circuit for relay incomplete. Upon the end ot' the first impulse, that is, when relay 2-15 becomes energized, relay 208 will become (leenergized, but relay 210 being slow to release will not retract its arI-natures unless relay v208 remains ideeneligized. Upon the retraction of its ai'fmatures by relay 208, relay 2:19 becomes energized. Upon the second retraction otthe .ar-matures of relay 215, relay 20S again becomes energized and causes the deener-giiaation of relay 220 whereupon the circuit for relay 202 is now completed through the back contact and let hand armature of relay 220, the back contact and outer right-hand armature of relay 2-07, and the front Contact and left hand arniattu e of relay 2-16 to ground. As

. 1elay202 becomes ene ixed, the circuit for relay 2-01 is opened at the contacts oi the lel'tha-nd armature of relay 202-. heir relay 208 again becomes deenergized, relay eenengized, and when relay becomes e er-n'ized for the tlri-ml time, a circuit is established for relay 203 ext-ending from battery. the winding ot-relay 2-03, the inner right-{hand armature and front contact-of relay 202-, the front contact and le t t-ha-nd .a-rm-atune of relay 1220, back contact and outer right-hand armature or relay 207 to ground at the front contact and armature-o1 relay210. lu-a similar manner each olithe ureluys 20-1 to 206, will become enengtized -.can'respondingto the number of impulses sent so that with a train of six impulse-s, relay 200 will finally become energized. At the end of this series of impulses, relay 206 will remain energized through its winding the alternate contacts 051' its left-hand armature, the front contact and left-hand armature of relay 210, the front contact and lett-hand armature of relay 210 to ground. Relay 215 becomessteadily energized and relay 20S retracts its anmatures "followed a tter an interval by relay 210. Upon the retraction of its armaturesby clay relay 219 becomes energized. When at ay 210 retracts its armature, relay 7, which-is bridged :across the left-hand armature and contact of relay 2 0 becomes energized. The circuit is now in a stable -.condition awaiting further action bythe subscriber at station 101. This ac tion consists in hanging up his receiver :according to instructions and relay 217 will thereupon become energized in the manner in which relay 117 became energized. That is, a circuit is established {from gUOL1I1l,'t-l1 armature and back contact of relay 215, the front cont ct and rightahand armature of 1'elay2l6,'tlie left-hand armature and trout contact of relay 207, the left-hand armature and back contact of relay-1224c, the :normal contacts of the rightha-nd armature of relay 2-23, and the winding of relay 12-17 to battery and ground. .llelay 217 anaintains relay 210 in an energized position and, at the same time, causes the energization of relay 2-18. A source of plus pulsating curuent:226is connected through an internupter 221,, the front contact and outer right-hand armature of relay 218, the condenser 22S, and the winding of relay 225 to battery :and ground. "Relay 22 3 responds to this character of current and attracts its armature whereby a ground is placed on the inner IlQflllHl-lellfll armature of relay 21S intermittently in the same manner. Thus relays 219 and 220 are caused to go through their cycle of operations in a similar manner to relays 119 and 120. Upon each :turn, of relay 219, a groin-1d is-cxteuded from the outer righthand armature and front contact 01'' relay 217, the left-hauu-l armature and 'la'out contact of relay 218. the l'injht-lutnrl armature and front contact of relay 210, to the four relays marked 22.2, 2 12, 24-2- and 252 in parallel whereby these relays are sin-mltaueously energized. It will be noted that due to the ar-rangen-ient of the relays 210 and 220, relay 2 -2, as an example, is energized once tor every other closure of the circuit by the interrupter It will now be noted that when relay is deenergized, ground is extended through the back contact and left-hand armature of ooo ' talking battery' relay 222, the front contact and right-hand armature of relay 206, and thence through the hack contacts and outer right-hand arm-f relays 205 to 201 inclusive, the front contact and inner left-hand armature of relay 217, terminal 110, tip side of the line and thence through the bells of stations 101 and 104 in parallel. It will be noted, however, that station 104: will respond only to minus pulsating current, therefore, the bellat station 101 is the only one which will ring during this interval. I

As the interrupter 221 functions, and when relay 219 responds, relay 222 will attract its armatures, thereupon the ringing current connections will be changed so that minus pulsating current will now be connected to the ring side of the line in place of ground, and ground will be connected to the tip side of the, line in place of plus pulsating current. Minus pulsating current on the ring side of the line causes the bell at station 103 to ring. Thus, the bells at stations 101 and 103 will alternately ring as the relay 222 energizes and deenergizes. lVhen the called subscriber at station 103 responds by removing his receiver from its switch hook, relay 22 1'will be energized to attract its-armatures whereupon relay 223 will become energized through its righthand winding and, after it attracts its armatures, will remain energized through its lefthand winding. The circuit of relay 217 will be opened and relay 217 will retract its armatures bringing the relay 215 into circuit "with the subscribers line to supply The circuit of relay 218 is opened at the outer right hand armature and contact of relay 217, whereupon relay 218 becomes deenergized, leaving relays 219, 220 and 200 in. their energized conditions they being held through the groundat the left hand armature and front contact of relay 216. At the end of the conversation,

when both subscribers hang up their receivers on their switch hooks, relay 215 will become deenergized, followed shortly thereafter by the deenergization of relay 216. The ground will thereupon be removed from the conductor 209 and the selector switch 125 and the non-numerical switch 113 will be returned to normal.

For a complete understanding of the functioning of the four-party revertive set shown. in Fig. 2, the following table is pended. In the first column are given number ofimpulses which are sent by the calling subscriber, in the second column are given the relays of the series 201 to 206 inclusive which are energized through the receipt of these impulses,the third column is divided into two sub-columns and each of these is further divided into two columns. In the first sub-column is shown the combination of'ringing current for ringing the first station, the letter G standing for ground, the character standing for minus, and the character fstanding for plus pulsating current. In the column headed 1st station, is shown the combination of connections when the relays 222, 232, 24.2 and 252 are cleenergized and under the second column headed 2nd station, is shown the combination of connections when these relays are energized. The last column is subdivided into two columns headed respectively 1st station and 2nd station and shows the number of the stations which are alternately rung.

apthe Ringing currents. Stations rung.

Relay Impulses. ener- 1st sta. 2nd sta.

V glzed.

1st sta. 2nd sta.

tip ring. tip ring.

WVhat is claimed is: In a telephone system, a party line, a

plurality of substations connected thereto,

mitted by said substation impulse transmitters for extending said line, a ring-back device accessible to said switches, said ring- .back device comprising signaling means,

relays responsive to impulses transmitted 'by said substation transmitters for selectively controlling said signaling means to signal the calling and the called parties on said party line, an interrupter comprising a pair of relays successively energized in all possible combinations for alternately connecting said signaling means during one period to signal the called party and during another period to signal the calling party, a relay responsive to a line condition. created by the act of'the calling party in replacing his receiver on its hook for causing said interrupter to operate, a relay responsive to a line condition created by the act of the called or the calling party in subsequently removing his receiver from its hook for cutting off said signaling means, a relay responsive to said last-named relay for thereupon locking said interrupter out of service until said ring-back device is released, and releasing means responsive to a; line condition created by the act of both the calling and called parties in replacing their receivers on their hooks for restoring said ring-back device to normal and for releasing said automatic switches.

In witness whereof, I hereunto subscrihe my name this 11th day of August A. 1).,

SAMUEL B, WILLIAMS, J11. 

